Isn't 10.3 the first version that is introducing the new APFS file system? If so, couldn't that have something to do with it? Does each app need to compile for

Isn't 10.3 the first version that is introducing the new APFS file system? If so, couldn't that have something to do with it? Does each app need to compile for both supported file systems now? I am not a LLVM expert but someone with more expertise on this subject might be able to say. I just found it odd that no one else here had mentioned it. It is the big update for 10.3